Improve activity containers dump readability

- Add nicer tree structure to dumpsys output (similar to the SF layers
  dump)
- Highlight non-default activity types (not undefined/standard) and
  windowing modes (not undefined/fullscreen)
- before: https://paste.googleplex.com/5934017719828480
  after: https://paste.googleplex.com/4688928846643200

Fixes: 315212110
Test: dumpsys activity containers
Change-Id: I46517005c5a23efb4e238ba9b70d3d4e79d99d41